Artificial intelligence (AI for short) is a new technical science studying and developing theories, methods, techniques and application systems for simulating, extending and expanding human intelligence. The artificial intelligence is a branch of computer science, which attempts to know the essence of intelligence and to produce a new intelligent machine capable of acting in a same way as human intelligence. The researches in this field include robots, speech recognition, image recognition, natural language processing and expert systems, etc., in which one of most important aspects of AI is the speech recognition technology.
At present, mature speech recognition technologies are mostly applied in near-field environment, i.e., a situation in which a user is close to a microphone, and a recognition rate is relatively high. However, when the user is in a far-field environment, for example, the user is 3 meters, 5 meters or farther from the microphone, speech recognition performance of existing speech recognition models or systems may drop dramatically.
At present, a noise-adding training mode is mostly used, in which speech signals in a far-field scene are simulated, and an acoustic model is re-trained according to training data, such that the re-trained acoustic model is suitable for the far-field scene. However, this mode completely depends on the training data. Since the training data cannot cover all possibilities of interference factors such as noise, reverberation and the like, representation ability of this kind of model is limited, and speech recognition performance of this kind of model is also limited.